1. Field of the Invention
The present invention generally relates to a method and a device for washing a porous workpiece during an impregnation process thereof. More particularly, the invention relates to a method for washing a porous workpiece such as a cast or sintered article in an impregnation process thereof in order to fill up the pores, such as blowholes or pinholes in the workpiece, with an organic impregnant, as well as a device for performing same.
2. Description of Relevant Art
There are known, such as by Japanese Patent Application Laid-Open Publication No. 59-28503, systems which include in a process for filling in blowholes or pinholes in a porous workiece such as a cast or sintered article, a step of dipping the article in an organic impregnant to thereby impregnate the blowholes, pinholes, or the like with the impregnant. In such impregnation systems, the impregnation step has been placed as a final step in the workpiece machining line for the purpose of labor-saving and the elevation of productivity. It is desirable to automate the impregnation process in accordance with production line tactics of management.
In general, after being impregnated, the workpieces must be washed to remove excessive impregnant from their surfaces. Such a washing step is an important process that is needed to produce finished goods, and particularly affects the appearance, precision of machining, etc. of the product.
In such a washing process, it generally is difficult to remove impregnant that remains in blind holes such as drill holes or tap holes bored in the workpiece. The workpieces contained in a basket were moved up and down in the washing liquid to remove excessive impregnant adhering to the outer surfaces of the workpieces. Conventionally, a worker was required to blow air into each of the blind holes in the workpieces to thereby remove excessive impregnant still remaining in the hole. As a result, the step of washing was intricate and troublesome, as well as being inefficient. Improvement was desired to increase production efficiency.
Further, automatic devices for washing impregnated workpieces have already been tried including one that was adapted to cause violent streams during washing in the washing liquid itself, and also another which used a shower of hot water as disclosed in U.S. Pat. No. 4,384,014 by Young, patented on May 17, 1983. In either example, however, little effect is expectable unless the water streams hit the blind holes in the workpiece. In the case of simultaneously processing many workpieces, it was especially difficult to remove impregnant by washing because some of the workpieces shield parts of the remaining workpieces.
The present invention has been achieved to effectively solve such problems in conventional washing processes of impregnated porous workpieces. PG,4